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We Rescue a Smog-Era Nova and Give the Engine a Tune-Up

Rescue Resto

Tommy Lee Byrd Sep 26, 2017
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Sometimes you just feel sorry for an old car. At that point you have two choices: you can put it out of its misery or you can rescue it. The subject of this tech article is a 1974 Chevy Nova four-door, a car that someone might use as a parts car. It is certainly not a desirable car to restore, but when you find a 43-year-old car that doesn’t have a single spot of rust on the body it’s hard to toss it to the side. The car is downright ugly and it didn’t run (or stop) when we dragged it home. We decided to give the 145-horsepower small-block a quick tune-up.

Can you believe that a 350ci small-block could be smothered down to 145 horsepower? Neither can we and we’re hoping to give this mill a few more horsepower by eliminating the original emissions system, which included a smog pump, restrictive exhaust manifolds, and an EGR valve. We will replace the manifolds with Patriot headers and run a dual exhaust setup. To get the car running efficiently we yanked the original points distributor in favor of a PerTronix Flame-Thrower Stock-Look distributor, a Flame-Thrower coil, and PerTronix 8mm spark plug wires. We also gave it a new set of spark plugs, a quick rebuild on the Rochester two-barrel carburetor, and some fresh fluids.

As a byproduct of removing the emissions equipment our engine bay started looking better and better. After some serious degreasing and cleaning and a fresh coat of Chevrolet Orange paint the old small-block cleaned up nicely. We finished it off with a set of Holley’s new finned-aluminum valve covers and matching air cleaner. The 350 is much happier with its new ignition and exhaust, and we’re glad to have saved this old four-door from the crusher. Our rescue resto is complete, and now it’s time to hit the road and spread the joy that only a green-on-green 1974 Nova four-door with 145 horsepower can provide.

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1. Crusty would be the best word to describe the original 350ci small-block under the hood of this 1974 Nova. At the time of rescuing this forgotten four-door, the engine would spin over but needed some work to be roadworthy.

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2. Under the original air cleaner is a Rochester 2-Jet two-barrel carburetor. We gave it a fresh rebuild so we could fire the engine and see if it was worth saving. The old 350 seemed to be OK but definitely needed a new ignition system and some engine bay decluttering.

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3. Our first move was to dispose of the original emissions control system. These smog-era cars were wimpy from the get-go and the smog pump, EGR valve, and miles of vacuum hoses choked off even more horsepower. We used a body saw to cut the tubes off of the exhaust manifolds.

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4. The EGR valve was intact, but we’ll be removing it and filling the hole left behind in the intake manifold. After we get all of the smog equipment stripped away, we plan to vacuum all of the nuts, dirt, and junk out of the engine bay.

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5. Next, we can remove the plug wires and start the ignition system disassembly process. Before we got too carried away, we turned the engine over to the timing mark to ensure that the No. 1 cylinder is at top dead center.

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6. When we removed the cap we saw that the rotor was pointed to the No. 2 cylinder. This misalignment means that the distributor had been removed at some point and could also explain why the car wasn’t running well.

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7. Even though the stock points distributor was serviceable, we opted to toss it in favor of a new cast-aluminum “stock look” electronic distributor from PerTronix. The grimy, original distributor can go in the swap meet pile.

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8. The new PerTronix Flame-Thrower electronic distributor comes out of the box ready to install, complete with rotor button and cap installed. The only thing we’ll have to do is crimp ring terminals on the two wires and hook them up to the coil.

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9. Before we stab the new distributor into place it’s time to take care of some more housekeeping items to get this dirty small-block cleaned up. First on the list is removing the original exhaust manifolds.

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10. The driver-side exhaust manifold was easy to remove. We took out the six bolts and then used a Sawzall to cut the pipe just below the collector where it was easy to reach. Check out how far those smog tubes reach into the exhaust port!

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11. The passenger-side exhaust manifold bolts were pretty rusty, but thankfully all of them broke loose without snapping off in the cylinder head. We consider that a victory!

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12. We’re planning to completely remove the old exhaust system and run a dual exhaust system so we disposed of the rusty crossover pipe with a Sawzall. With the crossover pipe out the way, we cut the pipe near the passenger-side collector.

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13. With the pipe free, the exhaust manifold can be removed from the top or bottom side. Since our car has a giant box on the firewall for the air-conditioning system, we found it easier to lower it out from below.

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14. The more parts we stripped away, the uglier it got. Now is the time to tackle the dirty small-block with some degreaser and a wire brush to get it ready for a rattle-can restoration. A little bit of Chevrolet Orange paint and it’ll look as good as new.

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15. Things are already starting to look better as we drop the PerTronix Flame-Thrower Stock-Look distributor into the 350. Don’t forget to pour some thick oil on the distributor gear before dropping it into place.

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16. With the distributor dropped in and the rotor button pointed toward the No. 1 cylinder, we can install the PerTronix Flame-Thrower coil using the supplied chrome bracket. It attaches to the existing bolt holes in the intake manifold.

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17. The beauty of the PerTronix Stock-Look distributor is that it doesn’t look out of place in our stock engine bay. We love the distributor cap with the “window,” which is typically used for points adjustment. For this distributor, it’s strictly for decoration.

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18. The distributor comes with two ring terminals, which are installed on the distributor power wires. PerTronix leaves the wires a little long so that you may cut them to length and then add the terminals.

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19. It’s always a good idea to use shrink tubing when installing wires that could be exposed to heat and moisture. After the terminal is crimped, we slid the shrink tube over the connection and gave it a little heat.

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20. With the ignition system upgraded, we moved onto the headers, which we got from Patriot Exhaust Products. These headers are a low-cost solution to the ugly and restrictive exhaust manifolds.

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21. The driver-side header slides into place very easily. After a quick test-fit we installed the one-piece gasket and got the supplied header bolts started.

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22. We made sure that all six bolts are started before we fully tightening any of them. The Patriot headers have nice 3/8-inch flanges that offer a great seal. The mid-length Clippster design will work for our stock application and the 1 5/8-inch primary tubes and 3-inch collectors will allow the engine to breathe much easier.

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23. The passenger-side is a little trickier as our 1974 Nova has factory air conditioning. The factory air cars have a massive box hanging off the firewall that gets in the way of the header. We had two choices: bash the No. 6 primary tube or “relieve” the box.

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24. Finally, we can install a new set of spark plugs and install the PerTronix Flame-Thrower 8mm spark plug wires. We opted for the pre-assembled set in black. They were an excellent fit compared to the way-too-long, parts-store plug wire set.

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25. We installed a pair of Holley’s new finned valve covers and a matching air cleaner to finish off our Nova rescue project. We’re still rocking the two-barrel carburetor so we had to modify the base plate for the air cleaner but the new accessories certainly gave our engine a great look! Now it’s time for some fresh fluids and a trip around the block.

Photos: Tommy Lee Byrd

Sources

PerTronix Performance Products
San Dimas, CA 91773
909-599-5955
pertronix.com
Holley Performance Products
Bowling Green, KY 42101
866-464-6553
http://www.holley.com
Patriot Exhaust Products
909-599-5955
www.patriotexhaust.com

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